Formulas, Ingredients and Production of Cosmetics

Formulas, Ingredients and Production of Cosmetics

Hiroshi Iwata ! Kunio Shimada Formulas, Ingredients and Production of Cosmetics Technology of Skin- and Hair-Care Products in Japan

Hiroshi Iwata ERICA Co., Ltd. Saitama, Japan Kunio Shimada NOF Corporation Tokyo, Japan Technical translator Yuko Makuuchi ISBN 978-4-431-54060-1 ISBN 978-4-431-54061-8 (eBook) DOI 10.1007/978-4-431-54061-8 Springer Tokyo Heidelberg New York Dordrecht London Library of Congress Control Number: 2012947809 © Springer Japan 2013 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, speci fi cally the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on micro fi lms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. Exempted from this legal reservation are brief excerpts in connection with reviews or scholarly analysis or material supplied speci fi cally for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. Duplication of this publication or parts thereof is permitted only under the provisions of the Copyright Law of the Publisher’s location, in its current version, and permission for use must always be obtained from Springer. Permissions for use may be obtained through RightsLink at the Copyright Clearance Center. Violations are liable to prosecution under the respective Copyright Law. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a speci fi c statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. While the advice and information in this book are believed to be true and accurate at the date of publication, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein. Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com)

v Preface I have long wished to publish not an ordinary book but a really useful one for cosmetics researchers in the world, believing it is my mission as I have long worked in this fi eld. Today, many books are available from which readers can learn the basics of designing cosmetics formulations. However, most of the authors work or have worked for private companies, and thus the books do not contain the knowledge that constitutes companies’ secret know-how but only the contents for which the companies or organizations approved disclosure. I doubt whether the information is suf fi cient for readers to actually design cosmetics. The coauthor of this book, Mr. Hiroshi Iwata, is an old friend of mine. He is an independent consultant and learned about cosmetics by studying them himself over many years. He has given guidance to major cosmetics companies not only in Japan but also overseas. He can impart knowledge freely without being restricted by any organization. He is highly capable and has abundant knowledge about cosmetic formulation, and there are not many people like him even among highly experienced researchers. I believe Mr. Iwata is the most suitable person for writing this book, and I sincerely thank him for spending much time and effort in spite of his busy schedule. The translator, Yuko Makuuchi, is an experienced expert in Japanese–English translation of scienti fi c and technical writing. Dr. Daisaku Ikeda (President of Soka Gakkai International), who is my lifelong teacher and has received more than 300 academic awards from all parts of the world, said during an interview with Dr. Vincent Harding, “What is the real purpose of science? It is the happiness of the human being.” I believe that development of superior new cosmetics products as a result of hard, accumulated research work has led and will lead to the happiness of people. If this book helps people engaged in research and development of cosmetics formulations, those who work for cosmetics companies, and students studying cosmetics, it will be a great joy for me as an editor. Finally, I thank Dr. Shinichi Koizumi of Springer Japan KK for giving us an opportunity to publish this book. Tokyo, Japan Kunio Shimada

vii Preface Japan is one of the three largest cosmetics markets in the world. It holds a unique place in the global industry as it has its own set of regulations and technological strengths. Higher safety standards, among other factors, have had the positive impact of forcing more research and thus pushing the science of cosmetics to a very high level. Japan’s cosmetics industry continues to focus on fundamental research, relying on cosmetics companies themselves to utilize their superior know-how to bring innovation and re fi nement to cosmetics and cosmetics-related technologies. Today, young cosmetics researchers who have completed their graduate studies and have entered a cosmetics company are put through several years of training before they become quali fi ed to design cosmetics formulations themselves. They are trained so that they can design formulas not by a process of logic but by heart, like craftsmen, chefs, or carpenters. To the authors of this book, this kind of training seems a terrible waste of labor and time. To address this issue and allow young cosmetics scientists to design novel formulations and effectively bring greater diversity of innovation to the industry, this book provides a key set of skills and the knowledge necessary for those so inspired. The book will help readers prepare formulas at the ordinary commercial product level and then eventually design their own original, and possibly high-level, formulations. This volume is designed to provide the comprehensive knowledge and instruction to researchers, that is, the know-how necessary for designing cosmetic products. The book’s chapters cover a comprehensive list of topics and are divided as follows: Chap. 1 is on the basics of cosmetics, including ingredients and dosage. Chapter 2 describes the raw materials of cosmetics and their application, that is, how ingredients like oils, fatty acids, macromolecules, and glycols, among others, are used (there has been no book to-date describing actual applications). Practical techniques and technologies for designing and manufacturing cosmetics are given, as well as theoretical knowledge, in each of Chaps. 3–5. Chapter 3 describes emulsi fi cation, which is particularly dif fi cult. Chapter 4 is on sensory evaluations of cosmetic ingredients that determine consumer preference. Chapter 5 describes how to mix and compose formulas for each kind of commercial cosmetic product, among

viii Preface which are featured soap-based cleansers, shampoos, conditioners, creams, hair-care products, hair dyes, agents for permanent waves, and curling lotions. In summary, our work endeavors to instruct and inspire all enterprising cosmetics technicians to pursue further their passion for the industry and apply themselves in the following three areas: (1) the development and manufacture of hair-care and skin-care cosmetics, (2) the evaluation of raw materials, and (3) the design of cosmetics and consulting. The potential for innovation is great in Japan’s cosmetics industry. It is our hope that the high level of dedicated research continues and proliferates, especially in the fi elds of evaluation and development of high-grade, premium cosmetics products. Tokyo, Japan Kunio Shimada

ix Contents Part I Ingredients and Productions of Cosmetics 1 Developing the Formulations of Cosmetics............................................ 3 1.1 Classification and Categories of Cosmetics ...................................... 3 1.1.1 Parts of the Body ................................................................... 4 1.1.2 Efficacies and Effects ............................................................ 4 1.1.3 Purpose of Use ...................................................................... 4 1.1.4 Method of Use ....................................................................... 6 1.1.5 Properties and Product Forms ............................................... 6 1.2 Constituents of Cosmetics ................................................................. 6 1.2.1 Ingredients for Giving the Product Form .............................. 6 1.2.2 Ingredients for Stabilizing the Products ................................ 7 1.2.3 Ingredients for Giving Efficacies, Effects, and Concepts ............................................................ 7 1.2.4 Ingredients Acting on the Senses of Users ........................... 7 1.3 Categories of Cosmetics and Product Forms .................................... 8 1.3.1 Toilet Soaps and Cleansers ................................................... 8 1.3.2 Shampoos .............................................................................. 8 1.3.3 Conditioners .......................................................................... 8 1.3.4 Creams .................................................................................. 10 1.3.5 Leave-on Hair Care Products ................................................ 10 1.3.6 Cosmetics Mainly Consisting of Oil ..................................... 10 1.3.7 Facial Toner ........................................................................... 11 1.4 Points to Note for Using Ingredients in Cosmetics ........................... 13 2 Raw Materials of Cosmetics .................................................................... 21 2.1 Oils .................................................................................................... 21 2.1.1 Hydrocarbons ........................................................................ 22 2.1.2 Vegetable Oils and Fats ......................................................... 25 2.1.3 Waxes .................................................................................... 27

x Contents 2.1.4 Esters ..................................................................................... 32 2.1.5 Higher Alcohols .................................................................... 34 2.1.6 Fatty Acids ............................................................................ 36 2.1.7 Silicones ................................................................................ 39 2.2 Surfactants ......................................................................................... 39 2.2.1 Anionic Surfactants ............................................................... 40 2.2.2 Cationic Surfactants .............................................................. 50 2.2.3 Tertiary Amines .................................................................... 55 2.2.4 Amphoteric Surfactants ........................................................ 57 2.2.5 Nonionic Surfactants ............................................................. 60 2.3 Polymers ........................................................................................... 67 2.3.1 Structure of Polymers ........................................................... 67 2.3.2 Purposes of Using Polymers ................................................. 68 2.3.3 Dissolving Polymers ............................................................. 76 2.4 Glycols .............................................................................................. 77 2.4.1 Kinds of Glycols ................................................................... 78 2.4.2 Purposes of Using Glycols .................................................... 78 2.5 Other Ingredients .............................................................................. 80 2.5.1 Ingredients for Giving Efficacies, Effects, and Concepts ..... 80 2.5.2 Coloring Agents .................................................................... 81 2.5.3 Scenting Agents .................................................................... 81 2.5.4 Ingredients for Stabilizing Products ...................................... 81 References .................................................................................................. 86 3 Emulsions .................................................................................................. 87 3.1 Designing the Formulations of Emulsions ........................................ 87 3.1.1 Formulation of Emulsifiers ................................................... 88 3.1.2 Selecting Surfactants ............................................................. 89 3.1.3 Selecting Oily Constituents................................................... 91 3.2 Factors Affecting Viscosity and Stability and Preventive Measures ................................................................... 94 3.2.1 Separation and Viscosity Increase at High Temperatures ............................................................ 94 3.2.2 Separation and Viscosity Increase at the Room Temperature ...................................................... 94 3.2.3 Effects of Salts ...................................................................... 95 3.2.4 Factors Causing Destabilization of Emulsions ..................... 97 3.3 Emulsification ................................................................................... 98 3.3.1 Emulsification Method .......................................................... 98 3.3.2 Emulsification Device ........................................................... 99 3.3.3 Conditions of Emulsification ................................................ 99 Reference ................................................................................................... 102 4 Sensory Properties of Cosmetics ............................................................. 103 4.1 Expressions of Sensory Properties .................................................... 103 4.1.1 Classification of Expressions ................................................ 104

Contents xi 4.1.2 Favored Senses ...................................................................... 104 4.2 Sensory Evaluation ........................................................................... 105 4.2.1 Points to Note in Human Sensory Evaluation ....................... 105 4.3 Sensory Properties of Alkyl Groups ................................................. 108 4.3.1 Sensory Properties of Oils .................................................... 108 4.3.2 Sensory Properties of Surfactants ......................................... 109 4.3.3 Sensory Properties of Glycols ............................................... 110 Part II Formulas and Productions of Cosmetics 5 Practice of Designing Cosmetics Formulations ..................................... 113 5.1 Soaps and Cleansers .......................................................................... 114 5.1.1 Combinations of Ingredients and Products ........................... 114 5.1.2 Toilet Soaps ........................................................................... 114 5.1.3 Cream Soaps ......................................................................... 115 5.1.4 Liquid Soaps ......................................................................... 115 5.1.5 Viscous Soaps ....................................................................... 117 5.1.6 Cleansing Cosmetics ............................................................. 118 5.2 Shampoos .......................................................................................... 120 5.2.1 Purposes of Shampoo Formulation and Constituents ........... 120 5.2.2 Anionic Surfactants ............................................................... 121 5.2.3 Amphoteric Surfactants ........................................................ 122 5.2.4 Cationic Polymers ................................................................. 122 5.2.5 Pearlizing Agents .................................................................. 126 5.2.6 Influence of Salts ................................................................... 130 5.2.7 Thickeners and Bubble Stabilizers ........................................ 130 5.2.8 Ingredients for Improving the Feel of Use ............................ 130 5.2.9 Efficacious Components and Conceptual Components ........ 131 5.2.10 Stabilizers, Preservatives, and Acidity Regulators................ 131 5.2.11 Sensory Evaluation of Shampoo ........................................... 131 5.2.12 Methods of Adding Scenting Agents .................................... 132 5.2.13 Designing Shampoo Formulations ........................................ 132 5.3 Hair Conditioners .............................................................................. 139 5.3.1 Sensory Characteristics of Conditioners ............................... 139 5.3.2 Adjusting the Viscosity of Conditioners ............................... 140 5.3.3 Basic Prescriptions and Constituents .................................... 141 5.3.4 Sensory Evaluation ............................................................... 148 5.3.5 Prescriptions of Conditioners of Various Sensory Characteristics ....................................................................... 153 5.4 Skin Creams ...................................................................................... 157 5.4.1 Constituents of Skin Creams ................................................. 157 5.4.2 Investigation of Oily Constituents ........................................ 157 5.4.3 Selection of Emulsifiers ........................................................ 159 5.4.4 Addition of Polymers ............................................................ 163 5.4.5 Selection of Glycols .............................................................. 164

xii 5.4.6 Formulation of Low-Viscosity Creams ................................. 164 5.4.7 Formulation of Gel Creams .................................................. 165 5.4.8 Formulation of Massage Creams .......................................... 166 5.5 Leave-On Hair Care Cosmetics ........................................................ 167 5.5.1 Hair Creams .......................................................................... 167 5.5.2 Cationic Hair Conditioners ................................................... 171 5.5.3 Hair Waxes ............................................................................ 173 5.5.4 Hair Gels ............................................................................... 181 5.5.5 Hair Mist Liquids .................................................................. 192 5.5.6 Hair Oils ................................................................................ 198 5.6 Cosmetics Mainly Consisting of Oils ............................................... 200 5.6.1 Characteristics and Techniques for Designing Formulations .................................................. 200 5.6.2 Liquid Oil Cosmetics ............................................................ 201 5.6.3 Solid and Stick-Type Cosmetics ........................................... 204 5.7 Facial Toner ....................................................................................... 208 5.7.1 Sensory Characteristics of Facial Toner ................................ 208 5.7.2 Safety of Ingredients ............................................................. 208 5.7.3 Properties and Constituents of Facial Toner ......................... 209 5.8 Cosmetics not Containing Specific Ingredients ................................ 211 5.8.1 Transparent Shampoo Consisting of Ingredients of Vegetable Origin ............................................................... 212 5.8.2 Pearl Shampoo Not Containing Sodium Laureth Sulfate ...................................................................... 213 5.8.3 Shampoo Not Causing Buildup of Hair ................................ 214 5.8.4 Hair Conditioner Not Containing Specific Ingredients ............................................................... 214 5.8.5 Cream Using Food Additives as Surfactants ........................ 215 5.8.6 Gel Cream Not Containing Specific Ingredients .................. 216 Index ................................................................................................................ 219 Contents

Part I Ingredients and Productions of Cosmetics

H. Iwata and K. Shimada, Formulas, Ingredients and Production of Cosmetics: 3 Technology of Skin- and Hair-Care Products in Japan, DOI 10.1007/978-4-431-54061-8_1, © Springer Japan 2013 Abstract Cosmetics, which are daily applied on a part or all parts of the human body, require special knowledge and care for designing formulations. Ingredients should be combined so as to achieve the aimed effi cacies and effects and be appropriate for the purpose, body part on which the product is to be applied, and method of use. This chapter also exemplifi es the ingredients used for toilet soaps, cleansers, shampoos, rinse-off hair conditioners, leave-on hair care products, creams, oily cosmetics that do not contain water, and facial toner. All cosmetic products need to be temperature resistant and stable over a long period of time. Use of preservatives, pH regulators, chelating agents, and antioxidants should be carefully investigated. Stability must also be checked for changes in color, smell, and viscosity. Antiseptic effects must last long and secondary pollution after opening the pack also needs to be prevented. Keywords Effi cacies and effects • Ingredients • Limitations on inclusion of ingredients • Prohibited ingredients 1.1 Classi fi cation and Categories of Cosmetics Cosmetics are daily applied on a part or all parts of the human body. There are diverse products, whose properties and forms are designed based on the ef fi cacy and effects, the body part on which they are applied, and the purpose and method of use. According to the regulations on the manufacturing and sales of cosmetics in Japan, cosmetics are classi fi ed into the categories as shown in Table 1.1 . This chapter describes the basic concepts and knowledge of designing cosmetics formulations. Chapter 1 Developing the Formulations of Cosmetics

4 1 Developing the Formulations of Cosmetics 1.1.1 Parts of the Body Cosmetics are applied on the skin, hair, scalp, nails, lips, teeth, and eyelashes including the oral cavity and around the eyes. Recent trends of cosmetics development focus on products to be applied on body parts on which cosmetics were rarely used and those that have new values. Cosmetics developments in new fi elds require thorough understanding and investigation of the body part on which the cosmetics is to be applied, the materials used and formulations. 1.1.2 Ef fi cacies and Effects The Pharmaceutical Affairs Law prescribes the range of cosmetics ef fi cacy as shown in Table 1.2 (Pharmaceutical and Medical Safety Director Noti fi cation No. 1339, December 28, 2000). No other ef fi cacy or effect can be advertised for cosmetics. Cosmetics must not “cure” or “be effective against” symptoms and must be mild. Ef fi cacy expressions permitted to cosmetics include “keeps something,” “prevents something,” “gives something,” and “repairs something.” 1.1.3 Purpose of Use Users use cosmetics to “cleanse,” “beautify,” “change the appearance,” and “protect” the bodies and “make them attractive.” It should be noted that the purposes of use may differ from the ef fi cacy expressions under the Pharmaceutical Affairs Law. Table 1.1 Categories of cosmetics Hair care products Hair liquids, hair tonics, scalp-care products, hair dyes, shampoos, and hair conditioners Skincare products Toilet water, beauty essences, creams, lotions, suntan lotions, sunscreens, cleansers a Shaving lotions (facial), shaving lotions (body), facial conditioners, facial packs Cosmetic oils b , body conditioners, massage lotions Makeup products Foundations, bases, facial powders, lipsticks, eye makeup products, rouges Body makeup products Perfumes, colognes Perfumes, colognes Others Bath preparations, nail cosmetics, body powders a Of cleansers, facial cleansers are those for mainly cleansing the face b Cosmetic oils are those applied on the skin and do not include oils used on hair, such as camellia oil

1.1 Classification and Categories of Cosmetics 5 Table 1.2 Range of cosmetics ef fi cacy 1 Cleans the scalp and hair 29 Softens the skin 2 Prevents odor of the scalp and hair by giving fragrance 30 Firms up the skin 3 Keeps the scalp and hair healthy 31 Gives luster to the skin 4 Makes the hair springy 32 Smoothens the skin 5 Moisturizes the scalp and hair 33 Facilitates shaving 6 Keeps the scalp and hair moist 34 Cares the skin after shaving 7 Makes the hair soft and smooth 35 Prevents prickly heat (by applying powder) 8 Makes the hair easy-to-comb 36 Prevents suntan 9 Keeps the hair glossy 37 Prevents blotches and freckles by sunburn 10 Makes the hair glossy 38 Gives fragrance 11 Removes dandruff and itchiness 39 Protects nails 12 Suppresses dandruff and itchiness 40 Keeps nails healthy 13 Supplements and keeps moisture and oil in the hair 41 Moisturizes nails 14 Prevents trichorrhexis and split ends of hair 42 Prevents dry lips 15 Helps arrange hair and keeps the hair style 43 Smoothens the texture of the lips 16 Prevents static charge of the hair 44 Moisturizes the lips 17 Cleanses the skin (by removing the impurities) 45 Keeps the lips healthy 18 Prevents acne and prickly heat (by cleansing the skin) (cleanser) 46 Protects the lips. Prevents the lips from drying 19 Prepares the skin 47 Prevents chapped lips by keeping the lips moist 20 Smoothens the skin 48 Smoothens the lips 21 Keeps the skin healthy 49 Prevents dental caries (toothpastes used for brushing the teeth) 22 Prevents dry skin 50 Whitens the teeth (toothpastes used for brushing the teeth) 23 Contracts the pores of the skin 51 Removes dental plaque (toothpastes used for brushing the teeth) 24 Moisturizes the skin 52 Cleans the oral cavity (toothpastes) 25 Supplements and keeps moisture and oil in the hair 53 Prevents mouth odor (toothpastes) 26 Keeps the skin fl exible 54 Removes tobacco stains from teeth (Toothpastes used for brushing the teeth) 27 Protects the skin 55 Prevents tartar from accumulating on teeth (toothpastes used for brushing the teeth) 28 Prevents the skin from drying 56 Obscures wrinkles caused by drying of the skin Permitted ef fi cacy expressions of cosmetics, which do not need approval by the Pharmaceutical Affairs Law (Pharmaceutical and Medical Safety Director Noti fi cation No. 1339, December 28, 2000)

6 1 Developing the Formulations of Cosmetics 1.1.4 Method of Use Cosmetics are applied on a part or all parts of the body and are either left on, wiped off, or rinsed off. Most cosmetics are either rinsed off (rinse-off cosmetics) or left on (leave-on cosmetics); and the difference determines the safety level required to the products and the ingredients used. It should also be noted that there are restrictions on components and the concentrations depending on the part of the body on which the cosmetics is to be applied. See the Appendices of the Japanese Standards for Cosmetics of Japan at the end of this chapter. 1.1.5 Properties and Product Forms The properties and forms of cosmetics are decided based on the body part on which the product is to be used and whether is it to be rinsed off, wiped off, or left on, and so that users feel easy to use. Marketing aspects, such as containers and proposed lifestyles, may also be re fl ected in the properties and product forms. Main product forms include liquids, viscous liquids, milky lotions, creams, gels, waxes, solids, powders, and aerosols. 1.2 Constituents of Cosmetics Constituents of cosmetics include water, oils, silicones, surfactants, polymers, polyhydric alcohols, saccharides, organic solvents, acid and alkali salts, inorganic and organic powders, pigment colors, amino acids, proteins, plant extracts, vitamins, ultraviolet absorbers, chelating agents, preservatives, antioxidants, oxidizing and reducing agents, and aromatic essential oils. It is convenient to classify the constituents into those that give the product form, stabilize the product, have ef fi cacy and effects, and act on the senses of users. Ingredients of cosmetics are combined so as to achieve the aimed ef fi cacies and effects and be appropriate for the purpose, body part on which the product is to be applied, and method of use. The ingredients are outlined below and described in detail in Chap. 2. 1.2.1 Ingredients for Giving the Product Form The constituents that give a product its form are water, oils, surfactants, silicone, polyhydric alcohols, polymers, and powders. They constitute the major part of a cosmetic product, determine its form, and affect the feel of use (Table 1.3 ).

1.2 Constituents of Cosmetics 7 1.2.2 Ingredients for Stabilizing the Products Cosmetics contain ingredients for stabilizing the product and preventing deterioration. They are essential because cosmetics are used over a long period of time after opening the packet and have risks of degeneration and deterioration. Because cosmetics are applied on delicate parts of the body, such as the skin, they are required to be highly stable. The stabilizers are classi fi ed into antimicrobial agents, pH control chemicals, antioxidants, and chelating agents. 1.2.3 Ingredients for Giving Ef fi cacies, Effects, and Concepts Cosmetics are not allowed to be advertised for ef fi cacy or effect, but ingredients that give ef fi cacy and effects can be added. Such ingredients are also essential for presenting the concepts and purposes of the product. Care should be taken that expressions are strictly within the permitted “Range of cosmetics ef fi cacy.” Each cosmetics manufacturer uses original combinations of ingredients that give ef fi cacy, effects, and concepts. Manufacturers also use original components and advertise the use to attract users. The ingredients can be broadly classi fi ed into plant extracts and herbal medicine components, microbial-derived ingredients, proteins and amino acids, ceramides, and vitamins. 1.2.4 Ingredients Acting on the Senses of Users Besides the major ingredients listed above, most cosmetics contain coloring and scenting agents to act on the senses of users. Coloring agents are used in hair dyes and also to give colors to cosmetics products. Only the latter is described in this book. Table 1.3 Ingredients for giving product forms Principal materials Principal objective of use Oils Hydrocarbons, waxes, esters, vegetable oils and fats, higher alcohols, fatty acids Oily ingredient, emulsifying aid Surfactants Anionic surfactants, amphoteric surfactants, cationic surfactants, nonionic surfactants Detergent, foaming agent, emulsi fi er, solubilizer, penetrating agent, softening agent, antistatic additives, antimicrobial agent Silicones Slip agent, antifoaming, texture improvement Polyhydric alcohols Moisturizing agent, stabilizer, solvent, solubilizing aid Polymers Thickener, setting agent, emulsion stabilizer, texture improvement Inorganic powders Powder, covering, coloring

8 1 Developing the Formulations of Cosmetics 1.3 Categories of Cosmetics and Product Forms The ingredients of cosmetics are combined so as to give the aimed product form, which depend on the category of cosmetics (shampoos, conditioners, creams, facial toner, body shampoo, lipsticks, foundations, etc.), and to match the purpose of the product. The ingredients used are exempli fi ed below separately for toilet soaps, cleansers, shampoos, rinse-off hair conditioners, leave-on hair care products, creams, oily cosmetics that do not contain water, and facial toner. 1.3.1 Toilet Soaps and Cleansers Toilet soaps and cleansers are for removing fi lth from the skin. There are toilet soaps, which are solid, and body shampoos and facial cleansers, which are either cream or liquid. Fatty acid salts are the most widely used component. Some products contain anionic or amphoteric surfactants as the cleansing component, in most cases together with fatty acid salts. Glycols such as glycerin are used as moisturizer. Higher alcohols and nonionic surfactants are combined to make the product creamy. Polymers are used to increase viscosity (Table 1.4 ). 1.3.2 Shampoos Shampoos are for cleansing the scalp and hair. Anionic surfactants are used as the major cleansing agent, and amphoteric surfactants are also combined as the second cleansing agent. Nonionic surfactants such as alkanol amides stabilize foams and increase viscosity. Cationic polymers increase viscosity and improve the feel of use. These four main constituents determine the product form and the feel of use. Silicones are also widely used to improve the touch (Table 1.5 ). 1.3.3 Conditioners Conditioners are applied after shampooing hair and are also called “hair treatment,” “hair pack,” and “hair rinse” depending on the contents of proteins, amino acids, and other effective components for repairing hair damage. The main purpose of conditioners is to improve the touch of hair and repair damage. Cationic surfactant of quaternary ammonium salt is always added to emulsify the product and improve the touch. Higher alcohols and all kinds and natural oils and fats can also be added to make the product creamy and improve the feel of use. Silicone is indispensable for giving a smooth touch to the hair. The most common form of conditioners is creams of various degrees of viscosity (Table 1.6 ).

1.3 Categories of Cosmetics and Product Forms 9 Table 1.4 Basic formulations of soaps and cleansers Toilet soap Fatty acids or oils 60–70% Beef tallow: 80%, coconut oil: 20% Glycerin 0–8% Also add sucrose or other saccharides as necessary Sodium hydroxide 18–22% of the fatty acids or oils Chelating agent (EDTA-4Na) (EDTA-4Na) Liquid soap Fatty acids or oils mainly consisting of lauric acid 5–25% Emulsi fi er, touch improver Glycerin 1–6% Stabilizer, viscosity adjuster, moisturizer Chelating agent (EDTA-4Na) (EDTA-4Na, sodium citrate) Potassium hydroxide 20–23% of the fatty acids or oils Anionic surfactants Foaming agent Amphoteric surfactants Stimulus reducer Nonionic alkanol amide surfactants Thickener, foam stabilizer Preservative Cream cleanser Fatty acids 5–20% Detergent Glycerin 1–6% Moisturizer, stabilizer Sodium hydroxide 20–23% of the fatty acids or oils Anionic surfactants 0–20% Detergent, foaming agent Amphoteric surfactants 0–12% Touch improvement, hair protection, and stimulus reduction Nonionic surfactants 3–6% Thickener, foam stabilizer Chelating agent Preservative Puri fi ed water Table 1.5 Basic formulations of shampoos (and body soaps) Fatty acids 0–25% Detergent Anionic surfactants 3–9% Detergent, foaming agent Amphoteric surfactants 1–4% Detergent, stimulus reducer, foaming agent Nonionic surfactants 1–6% Thickener, foam stabilizer Glycol 1–6% Stabilizer, viscosity adjuster, moisturizer Polymers 0–1% Thickener, touch improver Neutralizer, pH adjuster Chelating agent Preservative Water

10 1 Developing the Formulations of Cosmetics 1.3.4 Creams Creams are for caring the skin of the face, hands, and other parts of the body. Product forms may be creams, milky lotions and gels. The purposes are diverse and include repairing the skin from damage, moisturizing the skin, whitening the skin and blotches, and protecting the skin from ultraviolet rays. The oily components, which give the ef fi cacy and determine the feel of use, may be carbohydrates, esters, and higher alcohols. Nonionic surfactant and fatty acids are mainly used to emulsify the oily components. Polymers are added to stabilize the product form. Polyhydric alcohols are for moisturizing, and alkalis are combined to neutralize fatty acids (Table 1.7 ). 1.3.5 Leave-on Hair Care Products There are hair care products of diverse purposes, such as for caring hair, improving the texture and styling. Product forms are also diverse and range from liquids to solids. There are hair mists, hair creams, waxes, styling agents, and hair oils. Constituents vary depending on purpose and product form and can be all kinds of surfactants, oil, polymer, and glycol. Hair mists mainly consist of cationic surfactants and glycols. Hair creams contain oils, silicone, fatty acids (as emulsi fi er), and either anionic or cationic surfactants. Hair mists and creams also contain nonionic surfactants for emulsi fi cation. Hair waxes contain wax, micro crystalline waxes, fatty acids, nonionic surfactants, and glycols. Polymers are added to achieve hair setting and styling performances. Hair styling agents are gels or liquids that contain polymers. Hair oils are either silicones plus a small amount of plant oils or plant oils plus hydrocarbons (Table 1.8 ). 1.3.6 Cosmetics Mainly Consisting of Oil Cosmetic products that mainly consist of oils include cleansing oils, self-emulsifying bath oils, body massage oils, hair oils, lipsticks, and solid lip rouges. Main constituents Table 1.6 Basic formulations of conditioners Cationic surfactants 1–5% Hair softener, emulsi fi er, touch improvement Higher alcohols 2–10% Thickener, cream base Liquid oils 0–10% Oil, touch improvement Nonionic surfactants 0–1% Emulsi fi cation aid Silicone 1–10% Making the hair silky Polymers 0.5% or less Stabilizer, touch improver Preservative pH adjuster

1.3 Categories of Cosmetics and Product Forms 11 are oils of any kind and nonionic surfactants. The water content is very small if there is any. Formulation design involves combining oils that differ in polarity and melting points and adding nonionic surfactant HLB (Table 1.9 ). 1.3.7 Facial Toner Facial toner is designed by combining moisturizing agents so as to moisturize, soften, smoothen, fi rm up and give luster to the skin. It may also contain vitamin C derivatives for whitening, and fermentation extracts are included in some quasi-drug products for antiaging and wrinkle prevention. Many products also contain ceramides, vitamins, sterols, vegetable extracts, and other ef fi cacious components. Basic constituents are water, glycerin, and moisturizing agents, such as 1,3- butyl glycol, hydrolyzed collagen, amino acids, PCA-Na, and saccharides. Product forms may be transparent liquid, transparent and viscous liquid, and milky lotion. Table 1.7 Basic formulations of creams Cream Fatty acids 0–8% Emulsi fi er, thickener Higher alcohols 0–4% Thickener, base of the cream Esters 0–10% Oil, touch adjuster Carbohydrates 0–10% Oil Nonionic surfactant 1–4% Emulsi fi er Polymers 0.5% or less Stabilizer Preservative Alkali agent Water Gel Glycol 2–10% Moisturizer Ethanol 0–5% Solvent Polymers 0.3–2% Thickener, gelling agent Neutralizer 0.1–1% Alkali Preservative Water Gel Surfactants 20–50% Thickener, gelling agent Glycol 2–10% Solubilizer, touch improver Higher alcohol 0–10% Thickener Preservative Water

12 1 Developing the Formulations of Cosmetics Table 1.8 Basic formulations of leave-on hair care products Hair cream (soap emulsion type) Stearic acid 3–8% Higher alcohols 3–8% Thickener, good touch Esters 0–3% Touch adjuster Nonionic surfactant 0–1% Emulsi fi cation aid Silicone 1–8% To make the hair silky Anionic polymer 0–0.5% Stabilizer Preservative Alkali agent Hair treatment cream Cationic surfactants 1–5% Emulsi fi er, hair conditioner and smoother Higher alcohols 3–6% Thickener, good touch Esters 0–3% Touch adjuster Nonionic surfactants 0–1% Emulsi fi cation aid Silicone 1–8% To make the hair silky Vegetable oils and fats 0–1% To make the hair moist and soft Cationic polymers 0–1.2% Touch improver, stabilizer Antioxidant 0–0.1% Preservative pH adjuster Hair mist Glycol 2–6% Touch improver, moisturizer, stabilizer Cationic surfactants 0–1% To make the hair soft and smooth Esters 0–5% Nonionic surfactant 0–2% Emulsi fi er Setting polymers 0–15% Styling and setting agent Ethanol 5–20% Stabilizer, solubilizer pH adjuster Preservative Hair wax Fatty acids 2–8% Stearic acid, hydroxystearic acid Waxes 2–8% Candelilla wax, micro crystalline wax Esters 0–9% Higher alcohol 0–4% Nonionic surfactants 2–6% Emulsi fi er Glycol 0–6% Silicone 0–5% Preservative pH adjuster Hair gel Glycol 2–6% Ethanol 0–10% Thickening polymers 0.3–1.5% Mainly carboxy vinyl polymer Alkali agent 0.1–1% Preservative

1.4 Points to Note for Using Ingredients in Cosmetics 13 1.4 Points to Note for Using Ingredients in Cosmetics The Japanese Standards for Cosmetics (enacted in April 2001) prescribes the prohibited ingredients for cosmetics (Appendix 1) and limitations on inclusion of ingredients (Appendix 2), preservatives (Appendix 3), and UV absorbers (Appendix 4) to ensure the quality and safety of cosmetics. For each ingredient, there is a limitation on the amount that can be included depending on the body part the product is to be used and the method of use (to be rinsed off or left on). There are also restrictions on materials of biological origin. The former Japanese Standards for Cosmetic Ingredients should also be referred to because there were ingredients whose inclusion was restricted due to safety problem. All cosmetic products need to be temperature resistant and stable over a long period of time. Use of preservatives, pH regulators, chelating agents, and antioxidants needs to be investigated. Stability must be checked for changes in color, smell, and viscosity. Antiseptic effects must last long, and secondary pollution after opening the pack also needs to be prevented. Other points to note on the ingredients of cosmetics are summarized in Table 1.10 . Table 1.9 Basic formulations of cosmetics mainly consisting of oil Solid type Liquid oils 20–100% Waxes 0–30% Nonionic surfactants 0–25% Emulsi fi er Hair oil Silicone 90–100% Liquid oils Minute to small amount Table 1.10 Points to note about cosmetic ingredients Not irritate or be toxic to the skin Not disturb the physiological functions of the skin Be stable and not undergo changes in color and smell Not separate, not coagulate, not precipitate, and not undergo changes in property Not undergo big changes in viscosity by passage of time or temperature changes Suppress the development of bacteria and secondary pollution

14 1 Developing the Formulations of Cosmetics Standards for Cosmetics Appendix 1 Ingredients Prohibited in All Types of Cosmetics 1. 6-Acetoxy-2,4-dimethyl-m-dioxane 2. Antihistamines except those of aminoether type (such as diphenhydramine) 3. Ingredients derived from cattle and other ruminants raised in an area other than the following countries: USA, Argentina, India, Uruguay, El Salvador, Australia, Canada, Kenya, Costa Rica, Colombia, Singapore, Swaziland, Chile, Nigeria, Namibia, Nicaragua, New Zealand, Pakistan, Panama, Paraguay, Brazil, Botswana, Mauritius 4. Ingredients produced from the following parts of cattle or other ruminants: Pituitary, thymus, dura mater, pineal gland, spinal cord, placenta, intestine, brain, cerebrospinal fl uid, spleen, adrenal glands, tonsils, eyes, lymph nodes 5. Hormones and those derivatives except estradiol, estrone, and ethinylestradiol 6. Vinyl chloride monomer 7. Methylene chloride 8. Bismuth compounds other than bismuth oxychloride 9. Hydrogen peroxide 10. Cadmium compounds 11. Sodium perborate 12. Chloroform 13. Progrenolone acetate 14. Dichlorophene 15. Mercury and its compounds 16. Strontium compounds 17. Sulfamide and its derivatives 18. Selenium compounds 19. Nitrofuran-type compounds 20. Hydroquinone monobenzylether 21. Halogenated salicylanilide 22. Vitamin L1 and Vitamin L2 23. Bithionol 24. Pilocalpine 25. Pyrogallol 26. Inorganic fl uorine compounds 27. Pregnanediol 28. Local anesthetics such as procaine 29. Hexachlorophen 30. Boric acid 31. Formalin 32. Methyl alcohol

Appendix 2 Ingredients Restricted in All Types of Cosmetics Ingredient name Maximum amount of ingredient per 100 g Aluminum chlorhydroxy allantoinate 1.0 g Cantharides tincture, ginger tincture, or capsicum tincture 1.0 g as total Phenyl salicylate 1.0 g Polyoxyethylene laurylether (8–10 E.O.) 2.0 g Ingredients Restricted According to Types or Intended Purposes of Cosmetics Ingredient name Maximum amount of ingredient per 100 g Aerosol agents Zirconium Prohibited Cosmetics to be washed away immediately after use such as soap or shampoo Thiram 0.50 g Cosmetics other than those washed away immediately after use such as soap or shampoo Undecylenic acid monoethanolamide Prohibited Thiram 0.30 g Zinc p -phenolsulfonate 2.0 g 2-(2-Hydroxy-5-methylphenyl) benzotriazole 7.0 g Sodium lauroyl sarcosinate Prohibited Cosmetics used in cephalic, mucosa part or the oral cavity, and cosmetics used in other parts, containing lower aliphatic monoalcohols (exclude those containing the said alcohols added to dissolve ingredients in the said cosmetics) Estradiol, estrone, and ethinylestradiol 20,000 IU as total Cosmetics other than those used in cephalic, mucosa part or the oral cavity, containing no lower aliphatic mono - alcohols (include those containing the said alcohols added to dissolve ingredients in the said cosmetics) Estradiol, estrone, and ethinylestradiol 50,000 IU as total Cosmetics used in only cephalic part Aminoether type antihistamines 0.010 g Cosmetics other than those used only in cephalic part Aminoether-type antihistamines Prohibited Toothpaste Sodium lauroyl sarcosinate 0.50 g Compounds to be used with the purpose of emulsifying beewax or white beewax Sodium pyroborate 0.76 g (limited not to greater than 1/2 amount of beewax and white beewax) Compounds to be used for purposes other than emulsifying beewax or white beewax Sodium pyroborate Prohibited

16 1 Developing the Formulations of Cosmetics Ingredients Restricted According to Types of Cosmetics Maximum amount (g) of ingredient per 100 g Cosmetics not used for mucosa Cosmetics that may be used for mucosa Ubidecarenone 0.03 Prohibited Appendix 3 Ingredients Restricted in All Types of Cosmetics (continued) Ingredient name Maximum amount (g) of ingredient per 100 g Benzoic acid 0.2 Benzoate 1.0 as total Alkyldiaminoethylglycine hydrochloride 0.20 Photosensitizing dyes 0.0020 as total Chlorcresol 0.50 Chlorobutanol 0.10 Salicylic acid 0.20 Salicylate 1.0 as total Sorbic acid and sorbate 0.50 as total Dehydroacetic acid and dehydroacetate 0.50 as total Trichlorohydroxydiphenylether (Triclosan) 0.10 p -Oxybenzoic acid esters and their sodium salts 1.0 as total Phenoxyethanol 1.0 Phenol 0.10 Sodium lauryldiaminoethylglycine 0.030 Resorcin 0.10 Ingredients Restricted According to Types of cosmetics a Ingredient name Maximum amount (g) of ingredient per 100 g Cosmetics not used for mucosa and to be washed away Cosmetics not used for mucosa and not to be washed away Cosmetics that may be used for mucosa Zinc, ammonia, and silver-substituted zeolite b 1.0 1.0 Pantothenyl ethylether benzoate ○ 0.30 0.30

Appendix 3 17 Ingredient name Maximum amount (g) of ingredient per 100 g Cosmetics not used for mucosa and to be washed away Cosmetics not used for mucosa and not to be washed away Cosmetics that may be used for mucosa Isopropylmethylphenol ○ 0.10 0.10 Cetylpyridinium chloride 5.0 1.0 0.010 Benzalkonium chloride ○ 0.050 0.050 Benzethonium chloride 0.50 0.20 Chlorhexidine hydrochloride 0.10 0.10 0.0010 o- Phenyl phenol ○ 0.30 0.30 Sodium o -phenylphenate 0.15 0.15 Chlorhexidine gluconate ○ 0.050 0.050 Cresol 0.010 0.010 Chloramine T 0.30 0.10 Chlorxylenol 0.30 0.20 0.20 Chlorphenesin 0.30 0.30 Chlorhexidine 0.10 0.050 0.050 1,3-Dimethylol-5, 5-dimethylhydantoin 0.30 Alkylisoquinolinium bromide ○ 0.050 0.050 Thianthol 0.80 0.80 Thymol 0.050 0.050 ○b Trichlorocarbanilide ○ 0.30 0.30 p-Chlorphenol 0.25 0.25 Halocarban ○ 0.30 0.30 Hinokitiol ○ 0.10 0.050 Zinc pyrithione 0.10 0.010 0.010 Iodopropynyl butylcarbamate 0.02 0.02 0.02 Methylchloro isothiazolinone and methyl isothiazolinone solution d 0.10 N , N″-Methylenebis[ N¢ -(3- hydroxymethyl-2,5-dioxo4-imidazolidinyl)urea] 0.30 p -Dimethylaminostyryl heptyl methyl thiazolium iodide 0.0015 0.0015 Methyl isothiazolinone 0.01 0.01 Silver-copper zeolite e 0.5 0.5 Polyaminopropyl biguanide 0.1 0.1 0.1 a Blank indicates that it is prohibited to be used, and ○ indicates that there is no upper limit for the amount of ingredient b It indicates the compound containing 0.2–4.0% as silver and 5.0–15.0% as zinc when it is exposed to strong heat c It can be contained in cosmetics used for mucosa and only for oral cavity d It indicates the aqueous solution containing 1.0–1.3% of 5-chloro-2-methyl-4- isothiazolin-3-one and 0.30–0.42% of 2-methyl-4-isothiazolin-3-one e It indicates the compound containing 2.7–3.7% as silver and 4.9–6.3% as copper when it is exposed to strong heat Ingredients Restricted According to Types of cosmeticsa (continued)

18 1 Developing the Formulations of Cosmetics Appendix 4 Ingredients Restricted in All Types of Cosmetics (continued) Ingredient name Maximum amount (g) of ingredient per 100 g p- Aminobenzoic acid and its esters 4.0 as total Ingredients Restricted According to Types of Cosmetics f Ingredient name Maximum amount (g) of ingredient per 100 g Cosmetics not used for mucosa and to be washed away Cosmetics not used for mucosa and not to be washed away Cosmetics that may be used for mucosa Octyl salicylate 10 10 5.0 Homomenthyl salicylate 10 10 10 Methyl-2, 5-diisopropylcinnamate 10 10 Cinoxate ○ 5.0 5.0 Glyceryl mono-2-ethylhexonoate di- p -methoxycinnamate 10 10 Dihydroxydimethoxybenzophenone 10 10 Sodium dihydroxydimethoxybenzophenone disulfonate 10 10 Dihydroxybenzophenone 10 10 1-(3,4-dimethoxyphenyl)-4,4-di-methyl1,3-pentanedione 7.0 7.0 Dimethoxybenzylidenedioxoimidazolidine 2-ethylhexyl propionate 3.0 3.0 Tetrahydroxybenzophenone 10 10 0.050 2,4,6-Tris [4-(2-ethylhexyloxycar bonyl) anilino]-1,3,5-triazine 5.0 5.0 Methylbis(trimethylsiloxy)silyl iso-pentyl trimethoxycinnamonate 7.5 7.5 2.5 Amyl p -dimethylaminobenzoate 10 10 2-Ethylhexyl p -dimethylaminobenzoate 10 10 7.0 Isopropyl p -methoxycinnamate and diisopropyl cinnamate ester mixture g 10 10 2-Ethylhexyl p -methoxycinnamate 20 20 8.0 2-Hydroxy-4-methoxybenzophenone 5.0 5.0 Hydroxymethoxybenzophenone sulfonate and its trihydrate 10 h 10 h 0.10 h Sodium hydroxymethoxybenzophenone sulfonate 10 10 10

Appendix 4 19 Ingredient name Maximum amount (g) of ingredient per 100 g Cosmetics not used for mucosa and to be washed away Cosmetics not used for mucosa and not to be washed away Cosmetics that may be used for mucosa Phenylbenzimidazole sulfonic acid 3.0 3.0 4-tert-butyl-4 ¢ - methoxydibenzoylmethane 10 10 10 4- (2- b -glucopyranosiloxy) propoxy2-hydroxybenzophenone 5.0 5.0 Terephthalylidene dicamphor sulfonic acid 10 10 Ferulic acid 10 10 2-Cyano-3,3-diphenyl-2-propenoic aid 2-ethylhexyl ester (Octocrylene) 10 10 10 Drometrizole trisiloxane 15 15 2,2 ¢ -methylenebis(6-(2 H-benzotriazole2-yl)-4-(1,1,3,3-tetramethylbutyl) phenol 10 10 2-[4-(diethylamino)-2-hydroxybenzyl] benzoic acid hexylester 10 10 Dimethicodiethyl-benzal malonate 10 10 10 f Blank indicates that it is prohibited to be used, and ○ indicates that there is no upper limit for the amount of ingredient g It indicates the compound containing 72.0–79.0% of isopropyl p -methoxycinnamate, 15.0–21.0% of ethyl 2,4-diisopropyl cinnamate, and 3.0–9.0% of methyl 2,4-diisopropyl cinnamate h It is calculated as the total amount of hydroxymethoxybenzophenone sulfonate Ingredients Restricted According to Types of Cosmeticsf (continued)

H. Iwata and K. Shimada, Formulas, Ingredients and Production of Cosmetics: 21 Technology of Skin- and Hair-Care Products in Japan, DOI 10.1007/978-4-431-54061-8_2, © Springer Japan 2013 Abstract Raw materials used in cosmetics are described in this chapter. Oils used in cosmetics are hydrocarbons, animal and vegetable oils and fats, waxes, esters, higher alcohols, fatty acids, and silicones. The chemical structures and physical properties of oily ingredients and their effects on the feel of use and texture of products are described. Surfactants have both hydrophilic and lipophilic groups in a single molecule. The properties of each kind of surfactant are outlined, and the characteristics of major surfactants used in cosmetics are described. Polymers are widely used in cosmetics mainly for thickening and also for stabilizing, hair setting and improving the feel of use. The viscosity of polymers depends on the molecular weight, and the chemical structures of the hydrophilic group and alkyl chain determine the properties. Glycols have polarities that are intermediate of surfactants and are determined by the OH group and the number of carbons. They can be used for various purposes by using the properties and are very useful in preparing cosmetics. Keywords Animal and vegetable • Glycols • Oily ingredients • Polymers • Surfactants 2.1 Oils Most oils used in cosmetics can be broadly classi fi ed by chemical structure into hydrocarbons, animal and vegetable oils and fats, waxes, esters, higher alcohols, fatty acids, and silicones. The melting point, which is one of most important properties, is determined by the molecular weight; and oils of larger molecular weights melt at higher temperatures. Chapter 2 Raw Materials of Cosmetics

22 2 Raw Materials of Cosmetics Polarity, which is another property, is determined by the chemical and molecular structures (presence of double bonds and side chains and the kind of functional group) and the number of oxygen atoms. These properties determine the compatibility with other ingredients and govern the viscosity, consistency, and feel of use of the products. Oily ingredients also affect the appearance, hardness, and spread of the cosmetics. Therefore, oily ingredients can be said to determine the feel of use and texture of cosmetics products. This chapter describes the chemical structures and physical properties of oily ingredients and their effects on the feel of use and texture of products. 2.1.1 Hydrocarbons Hydrocarbons do not possess oxygen atoms, are saturated, and are thus nonpolar. The straight or branched chains consisting of carbon and hydrogen atoms can be combined in all cosmetics because they are scarcely oxidized and are hardly affected by pH changes and oxidation and reducing agents. They are useful as nonpolar oil for making emulsions. The chemical structure, melting point, and molecular weight of the hydrocarbon to be included should be examined for consistency with the purpose, properties, and feel of use of the product. 2.1.1.1 Isododecane Isododecane is unsaturated 2,2,4,6,6-pentamethylheptane (mw:170.3), which is free of aromatics, is highly hydrore fi ned and is easy to dry. It is highly compatible with dimethicone and is a useful solvent for highly polymerized silicones. It is fl ammable and should be kept away from fl ames. It gives a very light touch, and almost no feel is felt when applied on the skin. 2.1.1.2 Dodecane and Tetradecane Dodecane and tetradecane are straight-chain C12 and C16 hydrocarbons of vegetable origin (boiling point: 177°C, ignition point: 71°C, speci fi c gravity: 0.74–0.76, viscosity: 1–3[mPas]). They are fl ammable. 2.1.1.3 Squalane Commercially available squalane is produced from deep sea sharks, is liquid, melts at a low temperature, and has a structure in which both ends of hexamethyl tetracosane C 30 H 62 (mw: 422.8) branch. It gives a light touch and thus is suitable for leave-on cosmetics.

2.1 Oils 23 2.1.1.4 a -Ole fi n Oligomers a -Ole fi n oligomers are straight chains of C4–12 and resemble squalane. Like squalane, they give a light texture and are suitable for leave-on cosmetics. 2.1.1.5 Liquid Paraf fi n Liquid paraf fi n is straight-chain hydrocarbon of C16–32, consisting of paraf fi n and naphthene, and has a relatively low molecular weight. It gives a stronger oily and moisturized feeling than squalane and a -ole fi n oligomer. It is suitable for rinse-off cosmetics and for increasing the content of oily liquid hydrocarbon. 2.1.1.6 Vaseline (Petrolatum) White vaseline is saturated hydrocarbon of C24–34 prepared by dissolving petroleum in solvent and collecting the precipitated crystals. The melting point is at 38–60°C, and it is paste-like at the room temperature. It is suitable as an oily ingredient for creams, bases, and solid cosmetics that do not contain water. 2.1.1.7 Isoparaf fi n Isoparaf fi n is hydrogenated copolymers (C5–10) of iso-butene and n-butene. The transparent viscous liquid is classi fi ed by molecular weight into light liquid isoparaf fi n, light isoparaf fi n, liquid isoparaf fi n, and heavy liquid isoparaf fi n. Light liquid isoparaf fi n has low viscosity, dries easily and gives a very light texture. Due to its high compatibility with dimethicone, it can be used as an organic solvent. Heavy liquid isoparaf fi n is viscous and gives a strong sticky, adsorbing and heavy feeling. However, when combined in an emulsion, the heavy feeling disappears, and the product gives a stronger silky feeling than liquid paraf fi n. 2.1.1.8 Microcrystalline Waxes Microcrystalline waxes are isoparaf fi n and naphthenic hydrocarbons of C31–70 and have molecular weights of 450–1,000 and melting points of 60–85°C. Due to the branched chemical structure, the crystals are small. Those that melt at 80°C give a non-adsorptive and rather silky feeling; and those that melt at higher temperatures give stronger persistent feeling and less silky texture. It is important to choose the melting point by the purpose of use. Waxes are used for giving the form to stick-type cosmetics such as lipsticks and are also widely used in hair waxes. Those of high melting points produce waxes that can fi x the hair fi rm. They are also added into rinse-off hair conditioning products for enhancing the springiness.

24 2 Raw Materials of Cosmetics 2.1.1.9 Ceresin Ceresin is normal paraf fi n of C29–35. The hard crystals are produced by purifying ozocerite. The melting point is 61–95°C. Despite the high melting point, it gives a light feeling (Table 2.1 ). Table 2.1 Hydrocarbons used in cosmetics Name Basic structure, properties, composition Isododecane C 12 H 26 Dodecane Straight-chained hydrocarbon of C12 Tetradecane Straight-chained hydrocarbon of C16 Squalane C 30 H 62 a -Ole fi n oligomer Straight chain of C4–12 Liquid paraf fi n C16–32 Isoparaf fi n Light liquid isoparaf fi n, light isoparaf fi n, liquid isoparaf fi n, heavy liquid isoparaf fi n Microcrystalline wax Isoparaf fi nic and naphthenic hydrocarbons of C31–70 Isododecane C 12 H 26 Dodecane C12 Copolymer of rapeseed and Aleuritesfordii oils IV: 90, SV: 180 Isopentane C 5 H 12 a -Ole fi n oligomer Straight chain of C4–12 Hydrogenated diterpenes Hydrogenated copolymers iso-butenes and n-butenes. Light liquid isoparaf fi n of C5–10 Light isoparaf fi n Liquid isoparaf fi n Hydrogenated polyisobutene Heavy liquid isoparaf fi n Hydrogenated polydecene Straight-chained ole fi n oligomer of C4–12. Degree of polymerization: 3–6 Squalane C 30 H 62 . Hexamethyltetracosane. Derived from deep-water sharks Ceresin Produced by purifying ozokerite. Crystalline. Normal paraf fi n of C29–35. Melting point: 61–95°C Paraf fi n Normal paraf fi n of C16–40. Melting point 50–70°C Polyisobutene Polyisoprene Liquid polyisoprene Polyethylene Polymers of ethylene. Molecular weight: 2,000–5,000. Powders of polyethylene and high-melting-point polyethylene Polystyrene Polybutene Produced by decomposing and distilling naphtha and polymerizing butane and butene gases. Molecular weight: 500–5,500 Polypropylene Mineral oils (liquid paraf fi n) Paraf fi n and naphthene. C16–32 Petrolatum Precipitated crystals obtained by dissolving petroleum in solvent. C24–64. Paste-like substance Vegetable squalane C 30 H 62 . Produced by hydrogenating squalane extracted from vegetable oils such as olive, rice bran, wheat germ, and sesame oils Isohexadecane

2.1 Oils 25 2.1.2 Vegetable Oils and Fats Animal and vegetable oils and fats are triglycerides, which are esters of three fatty acids and glycerin. They are highly polar due to the three ester bonds. Many kinds are available. They are included in large amounts as a chief ingredient of cosmetics, or may be included in a very small quantity as a conception ingredient. To use them in cosmetics, the alkyl compositions should be understood, and appropriate oil should be selected based on purpose because the feel of use is determined by the alkyl composition and melting point. Vegetable oils and fats are especially prone to oxidization and changes in color by light, oxygen, and heat because the alkyl group has unsaturated fatty acids, which have a double bond(s) prone to oxidization. The iodine number is a useful index for knowing oxidization stability. Oils and fats that contain linoleic acid, which has three double bonds, have large iodine numbers and are especially prone to oxidization. Care should be taken in using natural fats and acids that have linoleic acid and large iodine numbers, and it is recommended to lower the pH or add antioxidants such as vitamin E and lecithin. Oils and fats that contain lauric acid and/or myristic acid, which have short alkyl chains, give a light touch. Solid fats that contain large amounts of palmitic acid and/ or stearic acid reduce lubrication. Liquid oils rich in unsaturated fatty acids, such as oleic acid, give a moisturized feeling. Table 2.2 lists representative vegetable and animal oils and fats. It is easy to understand the properties of the vegetable and animal oils and fats, which helps designing cosmetics formulations, by classifying them by the length of the saturated alkyl chains, iodine number and the distributions (and contents) of unsaturated acids, such as oleic, linoleic and linolenic acids. 2.1.2.1 Vegetable Oils and Fats Rich in Linoleic and Linolenic Acids Soybean oil and sun fl ower oil, which contain about 10% linolenic acid, have low melting points. Antioxidization measures should be taken when using them in cosmetics because the iodine number is large. Rapeseed oil has a relatively small iodine number because it contains more oleic acid that linolenic acid. 2.1.2.2 Vegetable Oils and Fats Rich in Oleic and Linoleic Acids Saf fl ower oil, which contains as much as 77% linoleic acid, and cotton seed oil and maize oil, which contain about 55% linoleic acid, require measures for preventing oxidization. Oils extracted from sesame and rice bran contain about 40% linoleic acid and 40% oleic acid and can be used in a large quantity in cosmetics by taking oxidization preventive measures.

26 2 Raw Materials of Cosmetics 2.1.2.3 Vegetable Oils and Fats Rich in Oleic Acid Oils extracted from avocado, olive, camellia, and rice bran, and persic oil contain at least 70% oleic acid. They have relatively low iodine numbers of 80–110 and are stable against oxidation and are thus suitable for cleansing and massage oil products, to which a large amount of oil must be prescribed. Because they give a moderate moisturized feeling, they are also used in hair care cosmetics. Antioxidants such as vitamin E and its derivatives are essential for products mainly consisting of oils, and the long-term stability must be checked. The oils can be added in creams by lowering the pH to the lowest level. They give a moderate moisturized feeling. 2.1.2.4 Vegetable Oils and Fats Rich in Lauric Acid Coconut and palm kernel oils contain approximately 50% lauric acid. They are prone to producing a unique sweet smell, and the stability should be con fi rmed before use. Solid oils give a light and dry feeling but are not widely used. 2.1.2.5 Vegetable and Animal Oils and Fats Mainly Consisting of Oleic and Palmitic Acids Palm kernel oil, which contains about 50% palmitic acid and 40% oleic acid, melts at 45°C and is solid at room temperature. It has a small iodine number and is stable against oxidation. Because it is solid fat, it gives a relatively heavy touch and reduces lubrication. It is not suitable for cosmetics that need to be soft and smooth. However, it is useful for giving a light and dry feeling and is suitable for hand creams and other non-silky products. Animal fats of similar compositions are beef tallow and lard. 2.1.2.6 Vegetable Oils and Fats Containing Palmitoleic Acid Macadamia nut oil is a rare vegetable oil that contains 25% palmitoleic acid. It has a small iodine number, a low melting point and relatively high oxidation stability. When used for hair care products, it provides a moisturized and soft feeling. It is an easy-to-use vegetable oil. 2.1.2.7 Vegetable Oils and Fats Containing Ricinoleic Acid Castor oil contains approximately 90% ricinoleic acid and is highly viscous. Because of the heavy feeling, it is unfavorable for skin care products that need to be refreshing. Inclusion of several percent is suitable for leave-on hair treatment products that aim for giving a strong moisturized feeling.

2.1 Oils 27 2.1.2.8 Vegetable Oils and Fats Containing Oleic and Steric Acids A typical fat of this group is shear butter. It contains 65% oleic acid and 20% stearic acid. It gives a moisturized and relatively heavy touch. Due to its small iodine number, it is stable against oxidization. It is useful for giving a moderate moisturized feeling to skincare and hair care products. 2.1.2.9 Vegetable Oils and Fats Containing Eicosenoic Acid Meadowfoam seed oil consists of long-chain fatty acids of about 60% eicosenoic acid and 15% erucic acid. It is stable against oxidization and gives a moisturized and persistent feeling. 2.1.3 Waxes Waxes are high-melting-point materials consisting of unsaponi fi able compounds such as hydrocarbons, fatty acids, alcohols and esters of fatty acids and higher alcohols that possess at least 20 carbon atoms in the alkyl group. They include beeswax, carnauba wax, candelilla wax, rice wax, lanolin, and jojoba oil, among many others. Due to the high melting points, they are useful for producing hard creams, pastes or stick-shaped products, such as nonaqueous lipsticks. Representative waxes used in cosmetics are listed in Table 2.3 . Beeswax, which is collected from beehives, is the most widely used wax in cosmetics. It contains fatty acids and becomes creamy when neutralized by alkali. It is used for creams either alone or combined with stearic acid. It may also be used for concealers and protection creams, which are entirely made of oily ingredients, and also may be combined with petrolatum and lanolin. It gives a moisturized and waxy touch. Carnauba wax has large numbers of carbons in both fatty acid and higher alcohol regions. It is used for solid cosmetics, particularly in products entirely made of oily ingredients, such as lipsticks and hair waxes. It is also used in some hair conditioner products to give a coated touch. It is dif fi cult to emulsify and may require both cationic and nonionic surfactants. Candelilla wax is used for solid cosmetics, lipsticks and hair waxes, which are entirely made of oily ingredients, and hair waxes to constitute 2–6%. The high melting point helps users to freely arrange the hair. Rice wax is used for solid cosmetics, lipsticks and hair waxes, which are entirely made of oily ingredients, like candelilla wax. Lanolin has been long and widely used in cosmetics. It contains hydroxy fatty acids as well as higher esters and has thus a water holding capacity. It is ef fi cacious because it contains sterols and is suitable for skin creams to give a moisturized touch. It is also very suitable for hair care products because it gives a good and moisturized texture. Jojoba oil is an ester consisting of unsaturated fatty acids and higher alcohol and is liquid at the room temperature. It is widely used in cosmetics products because it is stable against oxidization.

28 2 Raw Materials of Cosmetics Table 2.2 Vegetable and animal oils and fats used in cosmetics [ 2 ] INCI Laurate Myristate Palmitate Stearate Oleate Linoleate Linolenate Melting point Refractive index SV IV Characteristics Persea gratissima (avocado) oil 6.9 0.6 77.3 10.8 1.74 192.6 94.4 Contains vitamins A and E and has high ultraviolet absorption capacity. Penetrates into and spreads particularly well on the skin Prunus amygadu- lus dulcis (sweet almond) oil 6.7 1.2 66.3 22.3 1.46 188–200 92–105 Mainly consists of oleic acid and is slightly more unsaturated than olive oil. Low freezing point Olea europaea (olive) fruit oil 9.8 3.2 73.8 11.1 1.456 185–197 75–90 Mostly consists of oleic acid and contains squalane Theobroma cacao (cocoa) seed butter 35–36 1.457 185–199 Melts at around the body temperature (36–37°C). Has thus been used for lipsticks. Today, it is used for the base of creams Seamum indicum (sesame) seed oil 8.8 5.3 39.2 45.8 1.475 185–195 103–118 Oryza sativa (rice) bran oil 16.2 1.8 41.4 37.5 1.6 1.472 179–196 99–103 Carthamus tinctorius (saf fl ower) seed oil 6.8 2.5 12.6 77.4 −5 1.475 179–194 120–150 Butyrospermum parkii (shea butter) fruit 3 20 65 10 28–45 1.458 160–190 50–80 Contains tocopherol and vitamin E and prevents oxidization before puri fi cation. Melts at around the body temperature. Is low viscous and lubricous and penetrates well. Contains 4–11% unsaponi fi ed matters

2.1 Oils 29 (continued) INCI Laurate Myristate Palmitate Stearate Oleate Linoleate Linolenate Melting point Refractive index SV IV Characteristics Glycine soya (soybean) oil 10.4 4 23.5 53.5 8.3 −8 to −7 1.472 188–196 114–138 Usually used like olive oil (but is less stable than olive oil). Applied on the skin to protect to it from irritants and drying Zea mays (corn) germ oil 11.1 2.1 32.6 52.2 1.4 −8 to −10 1.474 187–198 88–147 Lowers the cholesterol content in the blood Brassica campestris (rapeseed) oil, canola oil 57.9 21.8 11.3 183–197 87–107 Contains much oleic acid. Nondrying oil. Resembles olive oil. Contains 1.7% erucic acid Prunus armeniaca (apricot) kernel oil, or Prunus persica (peach) kernel oil 7.2 2.3 74.8 15.6 1.471 188–199 91–110 Good-quality nondrying oil. Contains abundant oleic acid. Resembles almond oil Elaeis guineensis (palm) kernel oil 5.3 14 6.8 2 16 Carpylic acid 3 Capric acid 4 21–24 1.45 Lauric oil. Contains more oleic acid than palm oil and has the advantages of both coconut and palm oils Elaeis guineensis (palm) oil 49 2 41 7 30–50 1.466 Mainly consists of oleic and palmitic acids. Resembles beef tallow Ricinus communis (castor) seed oil 1 3.1 4.4 Ricinoleic acid 89.6 1.478 176–187 81–91 Contains a large amount of ricinoleic acid and is thus very viscous. Attracts moisture. Widely used in hair cosmetics and soaps Helianthus annuus (sun fl ower) seed oil 6.7 4 17.9 69.8 −18 to −16 1.47 186–194 113–146 Mainly consists of linoleic acid. High physiological activity Grapeseed oil 11.1 3.3 21.2 61.4 1.473 180–196 107–143 Macadamia ternifolia seed oil 1 7 3 55 2 Palmitoleic acid 25 1.47 190–200 70–80 Is a rare oil that contains at least 20% palmitoleic acid

30 2 Raw Materials of Cosmetics Table 2.2 (continued) INCI Laurate Myristate Palmitate Stearate Oleate Linoleate Linolenate Melting point Refractive index SV IV Characteristics Limnanthes alba (meadowfoam) seed oil Icosanoic acid 2, eicosenoic acid 66, docosenoic acid 20, docosadiene acid 10 160–175 90–105 Consists of long-chain fatty acids of 60% eicosenoic acid and 15% erucic acid. Stable against oxidization Gossypium (cotton) seed oil 20.1 2.4 18.9 56.5 1.474 189–197 88–121 Consists of 50% linoleic acid, 25% oleic acid and saturated fatty acids. Prone to oxidization due to high linolate content Moringa pterygosperma seed oil Agrees to the skin and gives smooth feeling. Further use in cosmetics expected. Superior oxidization stability Cocos nucifera (coconut) oil 47 18 9.5 2.9 6.9 Carpylic acid 7.7 Capric acid 6.2 20–28 1.449 245–271 7–16 Relatively stable against oxidization but rather prone to hydrolysis. Used in creams, shampoos, and conditioners. Important raw materials for producing laurate and myristate. When used in soaps, dissolves well in cold water and lathers well. Easy to saponify by hydroxyl alkali solution Arachis hypogaea (peanut) oil 11 2.9 42.2 34.7 2.6 Nondrying oil. Emollient effect. Equivalent penetration to olive and almond oil Beef tallow 7 26.6 18.2 41.8 3.3 1.457 190–202 25–60 Horse oil 3.2 24.9 5.5 35.5 10.8 9.5 1.463 195–204 71–86 Contains 7% palmitoleic acid Mink oil 5 21 3 42 6 1.469 190–210 75–90 Contains 6% myristoleic acid and 18% palmitoleic acid

2.1 Oils 31 Table 2.3 Waxes for cosmetics [ 2 ] Base, characteristics, properties, composition Speci fi c gravity Refractive index Melting point (°C) Acid value ratio a Saponi fi cation value Iodine number Unsaponi fi ed matter content (%) Orange raf fi a oil Fish of the Trachichtyidae family living in the deep seas of South Africa and Australia. Contains 80–90% esters (oleil alcohol and oleic acid) 0.855(40) – – 0.37 98–108 73–89 48 Carnauba wax Secretion from the leaves of carnauba palms in Brazil. Contains fatty acids of at least C24 and 85% of alcohol esters of C26, 28, and 30 0.990–1.001 1.469–72(40) 72–86 0.3–9.7 79–95 7–14 54–56 Candelilla wax Stems of a plant inhabiting northwestern Mexico and Texas. Consists of 45% hydrocarbons, 29% esters, and 26% others 0.982–0.986 1.455–1.461 68–72 46–65 10–22 Rice wax Wax produced from rice bran. Ester of C22 and 24 fatty acids and C24 to 34 alcohols – – 70–83 70–160 20 or less Jojoba oil Bush found in California and northwestern Mexico. Ester of unsaturated fatty acids and alcohols (C28–34: 83%) 0.853–0.875 1.455–1.475 0.75 80–110 70–100 50 Beeswax Fatty acids (C16–18: 70%) and alcohols (C28–34: 83%) 0.961–0.964 1.456–1.458 61–66 5–7.6 80–101 4–12 55–58 Lanolin Sheep wool. Mainly esters of hydroxyl fatty acids. Contains sterols 0.932–0.945 478–1.482 31–43 0.3–16 77–130 15–47 35–46 Reference: Courtesy of Nikko Chemicals a Acid value ratio is the ratio of ester value to oxidization

32 2 Raw Materials of Cosmetics 2.1.4 Esters Esters are oils consisting of fatty acids and alcohol, which are bound by ester bonds. Because they are combinations of fatty acids and alcohol, there are many ester compounds, which have one, two, or three ester bonds. The properties vary depending on the structure of the alcohol and fatty acid regions, the number of carbons and the number of esters. In general, branch-chained esters give more moisturized and smooth feeling than straight-chained esters. Because there are two oxygen atoms at the center of the molecule, esters have intermediate polarity between those of hydrocarbons and higher alcohols, and therefore esters are compatible with other ingredients. Care should be taken against esterolysis, which occurs in alkaline conditions. 2.1.4.1 Esters of Straight-Chain Fatty Acid and Straight-Chain Lower Alcohol This group includes isopropyl myristate, isopropyl palmitate, and butyl stearate. Because higher alcohols have low molecular weights, the properties and in fl uences of the fatty acid component are dominant. Isopropyl myristate and isopropyl palmitate are particularly widely used. 2.1.4.2 Esters of Straight-Chain Fatty Acid and Straight-Chain Higher Alcohol Cetylpalmitate and stearyl stearate are esters that have high melting points. When combined in creams, they give a dry, light and non-silky feeling rather than smooth and silky feeling. It can be combined with other oily ingredients of high melting points to provide a touch of fi rmness. 2.1.4.3 Esters of Branched-Chain Fatty Acid and Straight-Chain Alcohol There are myristylethylhexanoate, cetylethylhexanoate, and cetylisostearate in this group. They are suitable for rinse-off and leave-on cosmetics, skincare and hair care products for giving smooth, silky, and moderate moisturized feelings. They are the most widely used esters. 2.1.4.4 Esters of Straight-Chain Fatty Acid and Branched-Chain Alcohol This group includes ethylhexylmyristate, ethylhexylpalmitate, and isooctadecylpalmitate. They are used like the aforementioned esters consisting of branched-chain

2.1 Oils 33 fatty acid and straight-chain alcohol, but provide a slightly strong feeling of oiliness. Because they have the characteristics of both straight-chain and branchedchain esters, they have balanced characteristics and are useful for binding oils of different polarities. They are widely used in cosmetics because they have low melting points, are liquid in general, and give smooth and silky feelings. 2.1.4.5 Esters of Branched-Chain Fatty Acid and Branched-Chain Alcohol Isooctadecylisooctadecanoate and isononylisononate are highly compatible with silicone and form uniform liquid. They can also be used as a solvent for dimethicone. They give a light and silky feeling. 2.1.4.6 Esters of Fatty Acid and Polyhydric Alcohol Glycerylmonostearate is a typical ester of this group. They are important as nonionic surfactants and are widely used in cosmetics. They are effective emulsi fi cation aids. However, they deteriorate in alkali and cannot be formulated in high pH products. 2.1.4.7 Amphiphilic Esters of Carboxylic Acid and Alcohol Each member of this group, such as cetyl lactate and triethylcitrate, has its own characteristics. They can be used as carriers of solvents and ef fi cacious materials. Many amphipathic esters have been developed in recent years and used in diverse manners. 2.1.4.8 Dimer Acid Esters [ 1 ] Dimer acid esters have four ester bonds surrounded by four alkyl groups and are relatively stable in acidic and alkaline conditions. They provide a strong sticky and viscous feeling. They are easy to use combined with another ester. When combined with emulsi fi ers or other oily ingredients, they produce a persistent but smooth and favorable feeling. Due to the chemical structures, they are stable and suitable for combining in alkaline agents [ 1 ] . 2.1.4.9 Pentaerythritol Esters Due to their complicated chemical structures, pentaerythritol esters give a moisturized feeling. There are various forms including monoesters of alcohol and organic acid or fatty acid, such as isopropyl palmitate and cetylethylhexanoate, and diesters [ 2 ] .

34 2 Raw Materials of Cosmetics 2.1.5 Higher Alcohols Higher alcohols have a straight, branched, or unsaturated chain of carbons with an OH group at an end. In general, higher alcohols refer to those that have at least six carbons; and the larger the number of carbons, the more hydrophobic the alcohol is. They are used as the basic oily ingredient for emulsi fi cation in cosmetics. Particularly cetanol is widely used in creams and can control the viscosity of the product by the amount added. The length of unsaturated alkyl chain affects the viscosity and feel of use. Oleyl alcohol, which has a double bond, is suitable for low viscous products and gives an oily and strong moisturized feeling. Branched-chain alcohols such as hexyldodecanol, isostearyl alcohol, and octyldodecanol cannot be used as main oily components for forming emulsions. However they can be used in creams combined with saturated alcohol for adjusting the viscosity and feel of use. Higher alcohols used in cosmetics are listed in Table 2.4 . 2.1.5.1 Straight-Chain Alcohols Lauryl alcohol: This C12 alcohol melts at 25°C, gives a distinct sweet smell, and is rarely used for cosmetics. When used to make nonviscous cream of light texture, it is combined with other straight-chain alcohols, such as cetanol. Myristyl alcohol: This C14 alcohol melts at 35–42°C, is crystalline, and is almost odorless. It is used as a stabilizer, oily thickener, and emollient. Because it has fewer carbons than cetanol, it is more hydrophilic and gives a lighter and smoother feeling. It is suitable for leave-on skin and hair creams. It is more stable than lauryl alcohol and is almost odorless. Cetanol is the best higher alcohol for making creams, particularly for increasing the viscosity. The viscosity, temperature stability, and feel of use of the cream also depend on the content of cetyl alcohol (C16) and the alkyl compositions of other ingredients. Cetanol of 7:3 in C16:C18 is widely used. There is 99% C16 cetanol but it cannot be used alone because it turns into liquid at around the melting point and destabilizes creams. Use of C18 together with C16 results in wider alkyl distribution and better stability and resistance against deterioration and low and high temperature stresses. Stearyl alcohol is mainly C18 and is used like cetanol. The content of stearyl alcohol determines the viscosity, temperature stability, and feel of use of the cream. Arachidyl alcohol: This C20 higher alcohol is rare and is scarcely used in cosmetics except for some hair wax products. Behenyl alcohol has six more carbon atoms than cetanol, and thus has a higher melting point and is less polar. When the same amount is added, behenyl alcohol produces less viscous creams than cetanol and stearyl alcohol. It is useful for giving a soft and persistent texture. It can also be used for adjusting the hardness of solid

2.1 Oils 35 products that do not contain water. Because it has an OH group at the end of the alkyl group, it is compatible with low-HLB nonionic surfactants and stabilizes the products. Cetostearyl alcohol is a mixture of about 50% cetanol (C16) and 50% stearyl alcohol (C18). It is used like cetanol and stearyl alcohol. 2.1.5.2 Unsaturated Alcohol Oleyl alcohol (C18) has a double bond at the center of the alkyl group. It does not increase the viscosity of the cream when used alone. When combined with cetanol, it can produce soft cream that feels very oily and moisturizing. 2.1.5.3 Branched-Chain Alcohols Hexyl decanol is a C16 alcohol and has a short branched alkyl chain. It is rarely used in cosmetics. When combined in creams, it results in low viscosity. Addition of a large amount may spoil high temperature stability. The touch is light. Isostearyl alcohol is a C18 alcohol and has a branched alkyl chain. It gives a smooth and silky feeling when combined in creams. It is suitable for leave-on hair cosmetics. Octyldodecanol is a C20 alcohol and has a branched alkyl chain. It is widely combined in creams. It gives a very smooth texture and is suitable for both rinse-off and leave-on type cosmetics. Sterols: Cholesterol and phytosterol have sterol frameworks. Small amounts are used for giving a moisturized feeling and for helping emulsi fi cation. Table 2.4 Higher alcohols used in cosmetics Alkyl group Higher alcohol Molecular formula Molecular weight Speci fi c gravity Melting point n-6 Caproyl alcohol C 6 H 14 O 102.18 0.8191 −44.6 n-8 Caprylyl alcohol C 8 H 18 O 130.23 0.8254 −14.9 n-10 Caprylic alcohol C 10 H 22 O 158.29 0.8297 6.9 n-12 Lauryl alcohol C 12 H 26 O 186.34 0.8333 24.0 n-14 Myristyl alcohol C 14 H 32 O 214.39 0.8355 37.9 n-16 Cetyl alcohol C 16 H 34 O 242.42 0.8375 49.3 n-18 Stearyl alcohol C 18 H 38 O 270.50 0.8392 58.0 n-20 Arachidyl alcohol C 20 H 42 O 298.56 0.8405 65.6 n-22 Behenyl alcohol C 22 H 46 O 326.61 70.6 e-18 ¢ Oleyl alcohol C 18 H 26 O 268.49 0.8485 2.0 iso-16 Hexyldecanol C 16 H 34 O 242.00 iso-18 Isostearyl alcohol C 18 H 28 O 270.00 iso-20 Octyldodecanol C 20 H 42 O 298.00 0.84

36 2 Raw Materials of Cosmetics 2.1.6 Fatty Acids Fatty acids have a COOH group at one of its terminals and are thus highly polar. Because most of the commercially available ingredients for cosmetics contain fatty acids, it is important to know their alkyl compositions and choose suitable fatty acids for the purpose (check Tables 2.5 and 2.6 ). Because fatty acids react with other substances and may undergo saponi fi cation by alkalis or form complexes with cationic surfactants, the reactivity in formulation should also be examined. The high reactivity can be used for forming complexes and improving the feel of use. Lauric acid: This C12 straight-chain fatty acid melts at 28°C. It is used for manufacturing liquid soap cleansers and body soap products by neutralizing with potassium hydroxide in advance. Myristic acid: This C14 straight-chain fatty acid melts at 28°C. It is used together with lauric acid for manufacturing liquid body soap products by neutralizing with potassium hydroxide in advance. It is also used to produce soap creams by mixing with palmitic acid and steric acid and neutralizing with potassium hydroxide. Palmitic acid: This C16 straight-chain fatty acid is usually available in mixtures with stearic acid. Stearic acid: Mixtures of stearic acid and palmitic acid are the most widely used fatty acids in cosmetics, particularly creams. There are commercially available mixtures of various stearic to palmitic acid ratios, and those suitable for the purpose should be chosen. When used as the emulsi fi er of creams, high C18 content results in hard creams and coarse appearance. High C16 content produces smooth creams, but it is dif fi cult to increase the viscosity. Behenic acid: This C22 fatty acid has a high melting point and is dif fi cult to neutralize and saponify with alkali. Due to the large alkyl group, it is rather hydrophobic. It is rarely used in cosmetics. Oleic acid is an unsaturated fatty acid and has a double bond. It melts at 4°C and is easily oxidized. It is used in toilet soaps, liquid soaps, and cleansers. Combined with coconut oil fatty acids and lauric acids, it makes a suitable foaming and viscosity agent. Isostearic acid is a branched-chain liquid fatty acid and has better oxidation stability than oleic acid. It is suitable for liquid cosmetics. It is stable against oxidization in the liquid state and is suitable as a substitute of oleic acid for producing low viscous creams. Combination with straight-chain alcohol such as cetanol is essential. Fatty acids produced from coconut oil and palm-kernel oils consist of approximately 50% laurate, approximately 25% myristate, approximately 10% caprylic/ capric, and some oleic acid and palmitic acid. They are suitable for producing liquid soap by neutralizing with potassium hydroxide, which foams well and has strong detergency. They are also used for creamy cleansers.

2.1 Oils 37 Table 2.5 Fatty acids used in cosmetics Alkyl group Fatty acid Molecular formula Molecular weight Speci fi c gravity Melting point Neutralization number n-6 Caproic acid C 6 H 12 O 2 116 0.93 −3.0 484 n-8 Caprylic acid C 8 H 16 O 2 144 0.91 16.0 390 n-10 Caprylic acid C 10 H 20 O 2 172 326 n-12 Lauric acid C 12 H 24 O 2 200.3 0.8960(d60) 44.2 280.1 n-14 Myristic acid C 14 H 28 O 2 228.4 0.8622(d54) 53.9 245.7 n-16 Palmitic acid C 16 H 32 O 2 256.4 0.8487(d70) 63.1 218.8 n-18 Stearic acid C 18 H 36 O 2 284.5 0.8390(d80) 69.6 197.2 n-20 Arachidic acid C 20 H 40 O 2 312.52 75.3 180 n-22 Behenic acid C 22 H 44 O 2 340.6 0.82212(d100) 81.5 164.7 e-18 ¢ Oleic aid C 18 H 34 O 2 282.5 0.8905(d20) 13.4 198.6 i-18 Linoleic acid C 18 H 32 O 2 280 0.90 −18.0 200 Linolenic acid C 18 H 30 O 2 278 iso-18 Isostearic acid C 18 H 36 O 2 284.5 0.89(d20) 15 or lower 198 oh-18 Hydroxystearic acid C 18 H 36 O 2 300.5 76–77 186.7 Undecylenic acid C 11 H 20 O 2 184.3 0.9072(d25) 24.5 304.5 e-14 ¢ Myristoleic acid C 16 H 30 O 2 e-16 ¢ Palmitoleic acid C 18 H 34 O 2

38 2 Raw Materials of Cosmetics Table 2.6 Combinations of fatty acids and other ingredients and purpose of use Alkyl group of fatty acid Ingredients to combine Feel of use Stability Anionic surfactant Cationic surfactant Nonionic surfactant Fatty acids/higher alcohols n-12 For liquids (shampoos) For liquids For liquids and solubilization Liquids Coarse Increases smell n-14 Liquids, emulsi fi cation Smooth, lubricating Stable n-16 For creams For creams and liquids For creams Creams, emulsi fi cation Moisturized Stable n-18 For creams For creams and liquids For creams Creams, emulsi fi cation Moisturized Stable n-22 For creams (weak emulsi fi cation capacity) Hard creams Soft Stable e-18’ For low viscosity and solubilization Liquids, emulsi fi cation Oily, moisturized Prone to oxidization iso-16 Adjusting viscosity and texture Light, lubricating Stable iso-18 For creams and liquids Lubricating Stable iso-20 For creams and liquids Lubricating Stable oh-18 Gelatinization of oils

2.2 Surfactants 39 2.1.7 Silicones Silicones have a basic framework consisting of dimethylsiloxane, which is either circular or a straight chain. There are various forms such as monomers to which an amino group, alkyl group, POE or POP is introduced to a silica or carbon atom, copolymers and block polymers; and the variations are likely to increase further. Dimethicone is the polymer that forms the basic framework of silicone. The degree of polymerization is expressed with viscosity, which ranges from 6 cs to several million in materials for cosmetics. Low viscous dimethylsiloxanes of 6–10 cs improve the vanishing characteristics (phenomenon of becoming white when rubbed by hand) of creams without in fl uencing the texture. Those of 20–100 cs are oily and used for hair care products to increase lubrication. Dimethicones of 100–5,000 cs give a strong silky and smooth feeling. Those of 5,000 cs to tens of thousands cs give a persistent and silky smooth texture. Dimethylsiloxanes larger than 10,000 cs are highly viscous and are little compatible with other oily ingredients. They do not disperse uniformly and do not emulsify thoroughly. Therefore, there are premix products available, which are prepared by dissolving high-molecular-weight dimethicone in low-molecular-weight dimethicone and cyclomethicone, and are widely used for hair care products. Cyclomethicone (dimethyl cyclopentasiloxane) in the pentacyclic form is mainly used in cosmetics. It is used as a solvent of highly polymerized methylpolysiloxane and widely in skincare and hair care products. It gives a light and smooth texture. Due to its low boiling point (210°C), it volatilizes under heat, and methods should be carefully designed for adding cyclomethicone when producing cosmetics. Because it gives a very light touch, it is suitable for leave-on cosmetics. POE-POP dimethicones are nonionic surfactants consisting of dimethicone and POE-POP. They come in copolymers in which POE-POP group is bound at an end of dimethicone or in which POE-POP is added to a methyl group of the dimethyl end. They are used as nonionic surfactants for emulsifying creams and silicone gels. Their hydrophilic and hydrophobic properties, which are determined by the molar number of the POE-POP component, are used for improving the feel of use of shampoos and the silky feeling of water-base cosmetics. Amino-modi fi ed silicones have a structure in which an alkylamino group or its derivative is added to a methyl group of dimethicone. They are widely used for hair care products to give a good texture. The oily type is suitable for creamy conditioners. There is also a hydrophilic type, which is modi fi ed with polyoxyethylene and polyoxypropylene and is used for liquid cosmetics such as shampoos. 2.2 Surfactants Surfactants have both hydrophilic and lipophilic groups in a single molecule. Most surfactants have a lipophilic alkyl group consisting of 12–22 carbon atoms (C12–C22). Surfactants are classi fi ed by the ionization state (anionic, cationic, nonionic, and amphoteric) of the hydrophilic group. This chapter outlines the properties of each kind of surfactant and then describes the characteristics of major surfactants used in cosmetics.